Selecting the Correct
Agilent PLgel Column for
Polyolefin Analysis with GPC/SEC
Technical Overview
Introduction
Polyolefins range from low molecular weight hydrocarbon waxes to ultra high molecu-
lar weight rigid plastics. The molecular weight distribution of polyolefins is directly
related to physical properties such as toughness, melt viscosity and crystallinity. Gel
permeation chromatography (GPC) is widely accepted as the preferred technique to
fully characterize the molecular weight distribution of polyolefins.
The selection of a column set for the analysis of a polyolefin is dependent on the mol-
ecular weight range of the sample. Low molecular weight samples can be analyzed
using high efficiency, relatively low pore size columns. Higher molecular weight
materials require large particle size media to minimize shear effects, with a wide pore
size distribution.
Figures 1 to 4 show typical data for four different polyolefin samples, all obtained with
Agilent PLgel columns and the Agilent PL-GPC 220 high temperature GPC instrument.
Verified for Agilent
1260 Infinity
GPC/SEC System
Conditions for Figure 1
Samples
Linear hydrocarbons
Columns
2 × Agilent PLgel 3 µm 100Å, 7.5 × 300 mm (p/n PL1110-6320)
Eluent
TCB
Flow rate
0.8 mL/min
Inj vol
20 µL
Temp
145 °C
System
Agilent PL-GPC 220
2
0
25
min
1
2
3
4
5
Figure 1.
Separation of a selection of low molecular weight linear hydrocarbons on two
Agilent PLgel 3 µm 100Å columns.
KEY
1. C
32
2. C
24
3. C
20
4. C
16
5. C
12
Conditions for Figure 2
Sample
Hydrocarbon wax
Columns
2 × Agilent PLgel 5 µm MIXED-D, 7.5 × 300 mm (p/n PL1110-6504)
Eluent
TCB
Flow rate
1.0 mL/min
Inj vol
100 µL
Temp
160 °C
System
PL-GPC 220
3
0
21
min
Figure 2.
The chromatogram of a relatively low molecular weight hydrocarbon wax produced on two
Agilent PLgel 5 µm MIXED-D columns.
A molecular weight distribution of an intermediate molecular weight polyethylene
analyzed using three Agilent PLgel 10 µm MIXED-B columns is shown in Figure 3.
Conditions for Figure 3
Sample
Polyethylene
Columns
3 × Agilent PLgel 10 µm MIXED-B, 7.5 × 300 mm
(p/n PL1110-6100)
Eluent
TCB
Flow rate
1.0 mL/min
Inj vol
200 µL
Temp
160 °C
System
PL-GPC 220
4
0.0
0.8
0.4
0.6
0.2
1
5
log M
Figure 3.
The chromatogram of a relatively low molecular weight hydrocarbon wax on an
Agilent PLgel 10 µm MIXED-B two-column set.
Conditions for Figure 4
Sample
Polyethylene
Columns
4 × Agilent PLgel 20 µm MIXED-A, 7.5 × 300 mm (p/n PL1110-6200)
Eluent
TCB
Flow rate
1.0 mL/min
Inj vol
200 µL
Temp
160 °C
System
PL-GPC 220
5
0.0
0.4
0.2
0.3
0.1
4
8
log M
0.5
Figure 4.
A molecular weight distribution of an ultra high molecular weight polyethylene analyzed using
four Agilent PLgel 20 µm MIXED-A columns.
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Agilent shall not be liable for errors contained herein or
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Information, descriptions, and specifications in this
publication are subject to change without notice.
© Agilent Technologies, Inc., 201
5
Printed in the USA
April 30, 2015
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The molecular weight operating ranges and efficiencies for the columns are
summarized in Table 1.
Table 1.
Operating Ranges and Conditions for the PLgel Columns Used to Analyze Four Polyolefins
Agilent c olumn
MW operating range
Efficiency (plates/m)
PLgel 3 µm 100Å
Up to 4,000
> 100,000
PLgel 5 µm MIXED-D
200–400,000
> 50,000
PLgel 10 µm MIXED-B
500–10,000,000
> 35,000
PLgel 20 µm MIXED-A
2,000–40,000,000
> 17,000
These applications illustrate the diversity of polyolefin samples and indicate the
flexibility of the PLgel series of columns in addressing the analysis of such samples.
GPC/SEC Columns and Calibrants from Agilent
An alternative column choice for polyolefins is Agilent OligoPore, which exhibits
significantly increased pore volumes compared to conventional low pore size GPC
columns, for higher resolution in the oligomeric region.
Agilent offers a comprehensive portfolio of GPC/SEC columns and calibrants for
high-performance separations based on molecular size in solution. Agilent delivers
leading solutions for characterizing and separating polymers by GPC/SEC, and
manufactures all components for accurate polymer analysis.
Look at the Agilent Literature Library on www.agilent.com/chem/gpc-sec for a
comprehensive range of application notes and technical overviews to help you get the
best from your Agilent GPC/SEC columns and instruments.
